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find the equation of the Tangent line at (1,-1)?
9x^2-5xy-7=0 Idk if it makes a difference but ik ur supposed to use implicit differentiation
2 Answers
- ?Lv 78 years agoFavorite Answer
18x - 5[xy' + y] = 0
18x - 5xy' - 5y = 0
5xy' = 18x - 5y
y' = (18x - 5y)/5x
y'(1,-1) = (18 + 5)/(5) = 23/5
(y+1) = (23/5)(x-1)
Feel free to solve for y if you need slope intercept form
- 8 years ago
f(x,y) = 9x^2-5xy-7
18x - (5y + 5xy') = 0
18x - 5y = 5xy'
18x - 5y / 5x = y'
insert values for x and y
23 / 5 = slope
using y-y1 = m(x-x1)
y + 1 = (23/5) ( x - 1)
5y - 23x + 28 = 0 <---- equation of line in standard form
